sez [EMAIL PROTECTED]: >I'm still trying to figure out how something as simple as ((36-34.2)*100) >can be anything but 180, or how (as Alex put it) "the binary double >precision representation of 34.2 is inexact"... Perhaps a few details will help clear up this question.
.1 binary = .5 decimal .01 binary = .25 decimal .001 binary = .125 decimal .0001 binary = .0625 decimal .00001 binary = .03125 decimal .000001 binary = .015625 decimal etc Try it out and you'll discover that while .2 is a nice, inoffensive decimal number, it has a binary representation that turns out to be an infinitely repeating sequence, not unlike .111.... for 1/9 or .142857... for 1/7. Specifically, .2 decimal = .0011... binary. >and if it *is*, isn't there >any other form that could represent 34.2 exactly that's not binary double >precision? Yes. The cryptic abbreviation "BCD" stands for Binary Coded Decimal. It's what IBM based its character set EBCDIC on; if you check out the EBCDIC entry in the Jargon File, you may see one of the reasons why BCD has never caught on amongst hackers. _______________________________________________ use-revolution mailing list use-revolution@lists.runrev.com Please visit this url to subscribe, unsubscribe and manage your subscription preferences: http://lists.runrev.com/mailman/listinfo/use-revolution
